A chip-on-board (COB) type light-emitting module having the following configuration is proposed. Positive and negative wiring patterns are alternately provided on a module substrate. Semiconductor light-emitting elements connected in series such as chip-shaped light-emitting diodes (LEDs) are arranged between a pair of positive and negative wiring patterns. These LEDs are electrically connected to the wiring patterns by bonding wires. The wiring patterns, the LEDs, and others are buried by a translucent sealing resin.
In order to obtain white light from the light-emitting module, LEDs for generating blue light are generally used, and a sealing resin mixed with a yellow fluorescent material that is excited by blue light and emits yellow light is used as the sealing resin. Thus, the surface of the sealing resin functions as a white light-emitting surface.
The COB type light-emitting module comprising the above-mentioned configuration has the following problem.
That is, in this light-emitting module, a light-emitting system comprises LED rows arranged between the pair of positive and negative wiring patterns, and such light-emitting systems are provided side by side in the extending direction of the LED rows so that the LED rows are in matrix form. Therefore, the LED rows can be arranged in a substantially square region.
However, the above-mentioned configuration requires a space to keep an insulation distance between adjacent light-emitting systems. Moreover, as each of the light-emitting systems comprises the pair of positive and negative wiring patterns, the above-mentioned configuration also requires a space to arrange the individual wiring patterns. This leads to a greater space to arrange all the LEDs. Moreover, as the positive and negative wiring patterns are provided for each of the light-emitting systems, the number of wiring patterns is great, which is one of the causes of the high manufacturing costs.
Such a problem can be solved by providing a single light-emitting system, that is, by increasing the number of LEDs included in each LED row and providing one light-emitting system that comprises a single positive wiring pattern and a single negative wiring pattern across the LED rows. However, in such a configuration, a voltage applied to each LED row increases in response to the increase in the number of LEDs included in each LED row. The circuit configuration of a power supply unit for supplying such a high voltage has to be capable of resisting and supplying the high voltage. Therefore, the increase of costs is inevitable.